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Still Suffering from hesitation/bucking even after VANOS seals? Look Inside!

My car has suffered from a slight hesitation when taking off and under load, and also when suddenly accelerating under load at low rpm's up until 3k in 1st through 2nd even well after 3k miles on the beisansystems.com seals.

So I went in and looked at the MAF, cleaned it and also inside the connector I crimped down the pins inside so it would grab the receiving end pins better--that helped but the hesitation was still there.

Just 3 days ago I decided to clean and evenly crimped (using a pick) down the pins inside the connector for the exhaust VANOS solenoid; I took it for a spin and lo and behold the hesitation was pretty much gone! A few days went by and the more I drove the car the more low end torque it developed and it revved up smoother and smoother.

Yesterday, I did the same thing to the intake VANOS solenoid connector. Took it for a spin and the car felt as if the DME was relearning it's VANOS adaptations all over again! (felt sluggish at the beginning and started feeling stronger about 3 to 6 minutes later) 30 miles later the car feels great! and there is absolutely no hesitation under any circumstances!

The hesitation was caused due to shoddy and loose contact between the solenoid and it's receiving end [VANOS solenoid contacts]-- In other words

Quote:

Originally Posted by Optio

I believe that the issue is this..........

The contact width are set to the high side of the spec. The signal that is traveling across these contacts is quite weak. In other words, the current draw is very small. The device of interest, is not receiving the full signal strength from the PCM. Hence the sluggish performance of the VANOS. The best analogy that I can think of: Measuring the resistance of a conductor with a DMM. You will obtain one value when gently touching the conductor with the leads and a different reading when you press hard.

The pins inside both pigtails were spread open for some reason unknown to me.

The new found torque and instantaneous throttle response caught me off guard yesterday during a on and off drizzle when I punched it at 2750rpm in 2nd gear-- The rear end of the car kicked out to the side as if it had an LSD! (yes, I always drive with traction control off--at least when I can remember to turn it off.)

This is my MAF connector but the same concept applies to the VANOS connectors since they are the same in design.

You basically wedge a pick at the top and bottom of the filaments inside closing them together. Not all the way obviously but enough so that when it is plugged in it will open slighly and grab/bite the pins on the receiving end.

I've already done it to the image above. I don't have a before picture but the filaments were spread open and did not form a perfect rectangle as they do now.

Now after you have done so; Now when you are about to connect the pigtail you can feel some resistance ( which indicates the pins have a much better contact with the solenoid pins ) whereas before they simply just slid in like butter; Almost as if they were sliding into a void.

This trick would also work for MAF, DISA, IAT, Alternator pigtails, and all pigtails with the same design throughout the car.

Here's what Rajaie--Owner of besiansystems.com--had to say.

Quote:

Originally Posted by Rajaie

Congrats on the find and repair!
Thanks for sharing this important info!

I have not heard of this before. It seems reasonable it could be a problem.
There have been owners that complained of a hesitation that the vanos seals didn't resolve.

Some owners replace the vanos seals and receive little or no benefit. I know if they have another performance related problem they won't receive the benefits of the new seals until the problem is resolved. But in some cases it seems they have no performance problem. I've always wondered in these cases what is going on. Maybe what you found is a relevant cause.
Spray cleaning connectors with electrical contact cleaner is a good idea. But I had not considered crimping the pins.

This could be good news!! I am in the same boat with my car, Just bought it 2 weeks ago and my clutch pedal seems to feel softer and softer..... but i am seemingly getting more and more hesitation from my 1st gear takeoffs <3K rpms , Car has 107K Miles on it and not sure of the scheduled maintainence records... I am kind of thinking I may need to do the Vanos on my car, How easy/long does it take to get to the Vanos and or the pig tails ?

Great post and thanks for the contributions. However, I don't think "de-crimping" the connectors have any effect. Technically, the more snug/secure/tight your connectors are the better off it is (snug/secure/tight connector ensure that there is constant contact and connection).

What I recommend is just spraying your connectors with electrical contact cleaner.

Here is what I THINK (just my opinion) what happened. You had dirty/contaminated connectors such a dirt, oil, grease, etc that left a film preventing a 100% electrical efficient connection. while you were "de-crimping" your plugs you scratch/scrap/remove the film and thus made the connection more electrically effecient.

No need to get all upset, defensive or else I have to recommend you take some Midol. Again, great post. great pictures and thanks for the contributions.

Great post and thanks for the contributions. However, I don't think "de-crimping" the connectors have any effect. Technically, the more snug/secure/tight your connectors are the better off it is (snug/secure/tight connector ensure that there is constant contact and connection).

What I recommend is just spraying your connectors with electrical contact cleaner.

Here is what I THINK (just my opinion) what happened. You had dirty/contaminated connectors such a dirt, oil, grease, etc that left a film preventing a 100% electrical efficient connection. while you were "de-crimping" your plugs you scratch/scrap/remove the film and thus made the connection more electrically effecient.

No need to get all upset, defensive or else I have to recommend you take some Midol. Again, great post. great pictures and thanks for the contributions.

Where did the OP imply that the contacts were "de-crimped", spread apart, or otherwise loosened?

All my connectors under the hood are spread out just as you have described. I believe that this is normal and may or may not have anything to do with the electrical connection. I just tighten the VANOS contacts up slightly and will test drive it and to observe the change if any. I noticed that if you are not careful, you can easily push the contact down into the plastic assembly.

All my connectors under the hood are spread out just as you have described. I believe that this is normal and may or may not have anything to do with the electrical connection. I just tighten the VANOS contacts up slightly and will test drive it and to observe the change if any. I noticed that if you are not careful, you can easily push the contact down into the plastic assembly.

Are you having hesitation issues? Also keep in mind that this is what worked for me; nothing else was done in between. If it doesn't work for someone else then it means something else is off. But if everything checks out just fine then this is something to look at.

Post VANOS electrical contact crimping feedback! To begin with, I have noticed for the past 30,000 miles a loss of mainly low end torque (below 3000 RPM) as well as some high end loss. This was made worse as the weather warmed up. My fuel economy was down as too. I pulled my VANOS connectors and tighten them up slightly per the OP. I noticed immediately on the test drive that my low end was much stronger than I can recall and better yet, the high is rewarded with solid torque gains. I did a 75 mile loop at 75 MPH and I averaged 34 MPG based upon the OBC. Before this, my OBC MPG was 31.

I am convinced that the OP has discovered something. I run Lubro Moly or Pentosin full synthetic engine oil and this has preserved my Buna O rings. My buddy with his M52TU with 268000 miles does not have any oil leaks and no idle stumble when cold. The same for me, but I am only at 83,000 miles. I still agree with Raj that most engine oils will harden and shrink the Buna seals and result in the VANOS issues. The BMW dealer oil does crap out the seals and cause VCG leaks. I recommend that everyone switch over to the Made in German,y Lubro Moly or Pentosin branded full Synthetic oil.

Post VANOS electrical contact crimping feedback! To begin with, I have noticed for the past 30,000 miles a loss of mainly low end torque (below 3000 RPM) as well as some high end loss. This was made worse as the weather warmed up. My fuel economy was down as too. I pulled my VANOS connectors and tighten them up slightly per the OP. I noticed immediately on the test drive that my low end was much stronger than I can recall and better yet, the high is rewarded with solid torque gains. I did a 75 mile loop at 75 MPH and I averaged 34 MPG based upon the OBC. Before this, my OBC MPG was 31.

I am convinced that the OP has discovered something. I run Lubro Moly or Pentosin full synthetic engine oil and this has preserved my Buna O rings. My buddy with his M52TU with 268000 miles does not have any oil leaks and no idle stumble when cold. The same for me, but I am only at 83,000 miles. I still agree with Raj that most engine oils will harden and shrink the Buna seals and result in the VANOS issues. The BMW dealer oil does crap out the seals and cause VCG leaks. I recommend that everyone switch over to the Made in German,y Lubro Moly or Pentosin branded full Synthetic oil.

Good to know it worked for you and you noticed a difference! I was shocked such a small detail made a big difference.

Having some of the same symptoms. (Posted them just now in my introduction thread) First start up of day and the car accelerates well and has plenty of power. Once my temp needle reaches the middle of gauge (if thats what it is lol) then its down quite a bit on power and does kind of buck if i dont rev it at take off. Partial throttle is ok but still affected, half throttle is there kind of but anything past half and there is no difference in the acceleration (between half throttle and floored) characteristics. I will try this tomorrow nite and have more feedback.

Keep in mind that in my case I had completely broken in BESIAN systems VANOS seals and that I did not just crimp the connectors to fix the bucking. If you haven't done your seals and this doesn't cure it completely you more then likely have a combination of both shot seals and loose connector contacts.

There were absolutely no codes thrown; I did test my VANOS using DIS after 3k or more miles on new vanos seals and what I did notice was that the response time was off. I'll have to retest and see if the test results in better values.

Did it this morning. I was pretty skeptical at first but I can honestly say it made a difference for me. The pedal is more responsive from a dead stop. It used to be hesitant to the point where I thought my first gear or TC was showing early signs of dying. I am pretty surprised it made a difference but it did. I will point out that along with adjusting the metal prongs I also sprayed the 2 Vanos connectors and MAF connectors with some electronic cleaner. Thanks for sharing this OP.

here is my update. I was cleaning out my engine bay yesterday and I was like "what the heck...let's give this a try."

I decided to clean my connectors with electrical cleaners and "tighten" the female electrical prongs yesterday. I did this to my MAF, DISA, Exhaust Camshaft Sensor, Exhaust Camshaft solenoid, Intake Camshaft Sensor, Intake Camshaft solenoid, and crankshaft sensor connectors. I took my car out for a test drive and "WOW....i fell in love with my e46 again."

Now..to be fair...I am not sure if the gain/restore in performance is all psychological or whether it is attributed to the electrical contact cleaner. All I know is that I enjoyed driving my car again. I drove it for 45 miles in the country roads for about a hour with a huge grin on my face.

Did it this morning. I was pretty skeptical at first but I can honestly say it made a difference for me. The pedal is more responsive from a dead stop. It used to be hesitant to the point where I thought my first gear or TC was showing early signs of dying. I am pretty surprised it made a difference but it did. I will point out that along with adjusting the metal prongs I also sprayed the 2 Vanos connectors and MAF connectors with some electronic cleaner. Thanks for sharing this OP.

I just did it out of past experiences. I was shocked at the difference I felt.

Quote:

Originally Posted by flashtwosix

here is my update. I was cleaning out my engine bay yesterday and I was like "what the heck...let's give this a try."

I decided to clean my connectors with electrical cleaners and "tighten" the female electrical prongs yesterday. I did this to my MAF, DISA, Exhaust Camshaft Sensor, Exhaust Camshaft solenoid, Intake Camshaft Sensor, Intake Camshaft solenoid, and crankshaft sensor connectors. I took my car out for a test drive and "WOW....i fell in love with my e46 again."

Now..to be fair...I am not sure if the gain/restore in performance is all psychological or whether it is attributed to the electrical contact cleaner. All I know is that I enjoyed driving my car again. I drove it for 45 miles in the country roads for about a hour with a huge grin on my face.

I don't think it's psychological since several people; myself included have noticed exactly the same. Also, make note that the alternator, engine harness iirc share the same plug types.

I'm just since I haven't spend a dime on engine mods and the car just keeps getting stronger, smoother and more responsive with every small tweak and fixing nuances that would otherwise be there after dumping thousands on bolt-on engine mods.

I was skeptical too, but it does work and brings back the engine to its original state.

I believe that the issue is this..........

The contact width are set to the high side of the spec. The signal that is traveling across these contacts is quite weak. In other words, the current draw is very small. The device of interest, is not receiving the full signal strength from the PCM. Hence the sluggish performance of the VANOS. The best analogy that I can think of: Measuring the resistance of a conductor with a DMM. You will obtain one value when gently touching the conductor with the leads and a different reading when you press hard.